Method of drying goods



W. ATKINSON.

METHOD OF DRYING GOODS.

APPLICATION FILED OCT. 12, 1918.

Patented May 9, 1922.

initial vacuum after which the drying and WILLIAM ATKTNSON, OF BOXFORD,

MASSACHUSETTS, ASSIGNOR TO THE VACUUM COMPANY, OF SOMERVILLE,MASSACHUSETTS, A CORPORATION 01E MASSACHU- METHOD OF DRYING GOODS.

Specification of Letters Patent.

.Patented May 9, 1922.

Application filed October 12, 1918. Serial No. 257,855.

To all whom it may concern:

Be it known that 1, WILLIAM ATKINSON, of Boxford, in the county of Essexand State of Massachusetts, a citizen of the United States, haveinvented a new and useful Improvement in Methods of Drying Goods, ofwhich the following is a specification.

In certain types of drying it has been considered necessary, Where thegoods contain much moisture, to provide a condenser'between the drierand the vacuum pump which shall condense the moisture collected by theair in the process. This has resulted in considerable expense because ofthe amount of power used to run the pump to draw the air through thecondenser. My method is an improvement upon methods heretofore used sofar as I know, in that vapor'laden air passes from the heating chamberto a condensing thamber where it drops itsmoisture and circulatesbackthrough the heater to repeat the operation, which is continued asbelow described, a tank being provided to drain off the water or otherliquid of condensation. The use of a vacuum pump may thus be dispensedwith except to draw the condensation proceeds without the aid of a pumpas below described. I

My invention will be understood by reference to the drawings, in whichFigure l'is a longitudinal sectiomand Fig. 2 a cross section online '22of Fig.1. i The apparatus is divided into two chambers, one a heatingchamber and the other a condensing chamber, both forming part of thesame structure. The heating chamber in the accompanying drawing islettered A and the condensing chamber of substantially the same size islettered B. Both chambers as shown are cylindrical in shape. One wall aof the chamber A is preferably of steel and is surrounded-by a coveringof heat-insulating material C which. may be attached to it in anyconvenient manner. The outer end of this chamber is closed by a closurea bolted to the wall a and it alsofis covered with heat-insulatingmaterial C so that substantially no heat can be lost from this chamberexcept perhaps at its forward end.- Its forward end during the heatingoperation is closed by a vertically movable bulkhead D which closes,when desired, the front end of the chamber A but not airtight. It runsin vertical ways and may be raised and lowered as required to carry outmy process in any desired way as will be understood by one skilled inthe art. It has a small opening (1 preferably near its top connectingthe two chambers. --Both chambers may be provided with tracks A as shownin order that cars E loaded'with the material E to be, dried may be runinto the chambers.

At the rear or inner end of the chamber A there is provided a heater. Fconnectedto a suitable steam supply and a fan or blower G, the wholearranged within a hood H open at the bottom as at it so that the fan Gmay draw air intothe casing H from below and blow it out through thecoils F The platforms to the cars are preferably constructed of suitablewidth as at e to form a partition across the chamber, thus" making aduct (1 below the cars and requiring the air which chamber in thedirection of the arrows so as to establish'constant circulation.

By means of this portion of my apparatus the bulkhead D being inposition to close the chamber A. When the material is thoroughly heatedthe door D separating the heating chamber from the condensing chamber Bis raised. This chamber B is not insulated in any way and will ofnecessity therefore be much cooler than the chamber A and consequentlywill condense anv moisture which the air from the chamber A may bringinto it. The outer end of this chamber B is closed airtight by the gate6, and from that end of the chamber leads" a pipe J, which is connectedwith (not shown) and has a valve 7' by which it may be closed. Connectedto the lower end is circulated by the fan to pass around the a vacuumpump of the outer wall of the chamber B is; a pipe pipe connecting serveto draw ofi the contents of. the tank K when desired.

;To carry out my method by the use of this apparatus the material 'isplaced on the cars,

which preferably are run into and out of lation of air in the directionindicated by the arrows through this chamber, which will gradually heatthe goods to be dried. To make the heatpenetrate the material, forexample a bale of cotton or the like, the vacuum pump having beenstarted, a partial vacuum is drawn, say five inches, and thenimmediately let down to air pressure. This results in drawing out some,of the moisture from the bales, its place being taken by heat ed airwhen the vacuum is relieved] By doing this a number of times thematerial may be thoroughly heated to or above boiling at the vacuum itis planned to use in the final condensation process. 4

When the goods are thoroughly heated v the pressure in the chamber Bisreduced below atmospheric pressure by the pump to say ten inches orwhatever amount is desired in the two chambers after the bulkhead D israised to connect the chambers. The pump is then shut off by the valve9' and the apparatus is left in that condition for such atime asexperience has shown is desirable. The process then goes on inside thetank, that is to say, the moisture in the goods boils out and thecirculation of air containing the moisture is' maintained by the fan G,which constantly forces air through the heater.

The bulkhead should then be opened wide 01" sulficiently to allow freecirculation fr'om'one chamber to the other. The air is driven into thechamber B as shown by the dotted arrows where the moisture condensesbecause the chamber B is not and has not been heated and will never getas hot as the chamber A.

Circulation is constantly maintained by the fan and as the air and vaporpass into the chamber B and the vapor is condensed it is collected inthe tank K, the steam coil during this period being still maintained atits original or at. any given desired temperature so jas-to ,ensure themaintaining of the temper'ature in the chamber A, the condensation i hasbeen sufficiently'dried air at atmospheric maintaining the chamber.

When it is determined that the material pressure is admitted and thegate b is opened and the material removed the gate or bulkhead D beingraised,'ifthat has not already been done, or removed. L

It is evident that this method may be carried out by other apparatusthan that shown.

It employes features which I believe to be or increasing the [Vacuum ina free circulation of air between the two chambers and reducing thepressure in the two chambers below. atmospheric pressure, whereby themoisture in the goods will be vaporized and the air and vapor from saidheated-chamber will mingle with that in the condensing chamber and thevapor will be condensed, and circulating the vapor-laden air in the twochambersiwhereby it will carry the moisture' from the heating to thecondensing chamber, deposit it there and return to the heating chamberfor further heating, absorbing and condensing.

2. The method of drying above described which consists in heating thegoods to be dried to a predetermined temperature ina closed chamber atatmospheric pressure, reducing the pressure in said chamber to suchapoint that the moisture in the goods will be vaporized and absorbed bythe air in the chamber, causing the vapor-laden air to cir-- andreturning the air to the chamber to be reheated and to absorb othermoisture from the goods and continuing the process until the goods aresufficiently dried.

3. That improvement in the art of drying which consists in circulatinghot air around the materialto be dried in a closed chamber until thegoods are thoroughly heated to a high degree oftemperature then reducingthe pressure to such a point that the moisture in the goods will. bevaporized and absorbed by the air in the chamber and then condensing thevapor therefrom, and passing the dried air over the goods again wherebythe air will absorb other moisture'from the goods, and continuing theprocess untilthe goods are sufficiently dried.

4. That method of drying goods which consists in placing the goods in aclosedchamber, heating the air therein at atmospheric pressure wherebythe goods will be heated, reducing the air pressure and causing the airto circulate about the goods whereby the moisture will be withdrawn fromthe drop W cooling the air to cause. it to its moisture and reheating itwhereby it will absorb more moisture from the goods and again cooling itand. continuing the moisture-absorbing and dropping process until thegoods are substantially dried will 'be alternately withdrawn from thwhereby the\sameair will be used throughgoods and taken up by the heatedair, and 10 out the drying process; then condensed and the dried airreheated to 5. That method of drying goods under a take upmore moisturefrom the goods, and partial vacuum in a closed chamber, which the sameair under a'partial Vacuum used consists in alternately heating andcooling constantly until the drying is complete. the air while under apressure less than atmospheric pressure whereby the moisture WILLIAMATKINSON.

